Steven Yeun is crossing networks and genres for a good laugh: The Walking Dead star has recorded a guest role on American Dad, EW has learned. Yeun will play Charles, the assistant to Vincent, whose parents were murdered in the last installment of animated comedy’s saga known as “The Golden Turd.” The episode featuring Yeun, who also voices a character on Nickelodeon’s The Legend of Korra, will air later this season on Fox.